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Cerebral white matter lesions (WML) encompass axonal loss and demyelination and are assumed to be associated with small vessel disease (SVD)-related ischaemia. However, our previous study in the parietal lobe white matter revealed that WML in Alzheimer’s disease (AD) are linked with degenerative axonal loss secondary to the deposition of cortical AD pathology. Furthermore, neuroimaging data suggest that pathomechanisms for the development of WML differ between anterior and posterior lobes with AD-associated degenerative mechanism driving posterior white matter disruption, and both AD-associated degenerative and vascular mechanisms contributed to anterior matter disruption. In this pilot study, we used human post-mortem brain tissue to investigate the composition and aetiology of frontal WML from AD and non-demented controls to determine if frontal WML are SVD-associated and to reveal any regional differences in the pathogenesis of WML. Frontal WML tissue sections from 40 human post-mortem brains (AD, n = 19; controls, n = 21) were quantitatively assessed for demyelination, axonal loss, cortical hyperphosphorylated tau (HPτ) and amyloid-beta (Aβ) burden, and arteriolosclerosis as a measure of SVD. Biochemical assessment included Wallerian degeneration-associated protease calpain and the myelin-associated glycoprotein to proteolipid protein ratio as a measure of ante-mortem ischaemia. Arteriolosclerosis severity was found to be associated with and a significant predictor of frontal WML severity in both AD and non-demented controls. Interesting, frontal axonal loss was also associated with HPτ and calpain levels were associated with increasing Aβ burden in the AD group, suggestive of an additional degenerative influence. To conclude, this pilot data suggest that frontal WML in AD may result from both increased arteriolosclerosis and AD-associated degenerative changes. These preliminary findings in combination with previously published data tentatively indicate regional differences in the aetiology of WML in AD, which should be considered in the clinical diagnosis of dementia subtypes: posterior WML maybe associated with degenerative mechanisms secondary to AD pathology, while anterior WML could be associated with both SVD-associated and degenerative mechanisms.

INTRODUCTION The Alzheimer's Disease Neuroimaging Initiative (ADNI) has accumulated 15 years of clinical, neuroimaging, cognitive, biofluid biomarker and genetic data, and biofluid samples available to researchers, resulting in more than 3500 publications. This review covers studies from 2018 to 2020. METHODS We identified 1442 publications using ADNI data by conventional search methods and selected impactful studies for inclusion. RESULTS Disease progression studies supported pivotal roles for regional amyloid beta (Aβ) and tau deposition, and identified underlying genetic contributions to Alzheimer's disease (AD). Vascular disease, immune response, inflammation, resilience, and sex modulated disease course. Biologically coherent subgroups were identified at all clinical stages. Practical algorithms and methodological changes improved determination of Aβ status. Plasma Aβ, phosphorylated tau181, and neurofilament light were promising noninvasive biomarkers. Prognostic and diagnostic models were externally validated in ADNI but studies are limited by lack of ethnocultural cohort diversity. DISCUSSION ADNI has had a profound impact in improving clinical trials for AD.

Background Bone mineral density (BMD) is a potential surrogate marker of lifetime estrogen exposure previously linked to increased risk of Alzheimer dementia among elderly women. We examine the association between BMD in the "young old" with imaging biomarkers of brain aging and cognitive performance. Methods Offspring participants (N=1905, mean age 66) of a population-based cohort who had BMD, brain imaging and detailed cognitive assessment were included in the study. Sex-stratified, linear, and logistic regression models were used for analysis. Results Higher femoral neck BMD was associated with lower white matter hyperintensity burden and better performance on Trails B-A in both sexes, even after adjustment for cerebrovascular risk factors. Among women, the positive association with Trails B-A performance was seen only in APOE4 allele carriers. Higher BMD measurements were linked to better visual reproductions test performance in men. Finally, among women, higher femoral trochanter BMD was associated with better logical memory and Hooper visual organization test performance. Conclusion Among the "young old," higher BMD is associated with less white matter hyperintensity burden and better, domain-specific, cognitive performance. This suggests that lifetime estrogen exposure may modulate the degree of cumulative vascular brain injury independent of cerebrovascular risk factors.

OBJECTIVEEstimate the prevalence of mild cognitive impairment (MCI) and probable dementia in the racially and ethnically diverse community-based Northern Manhattan Study cohort and examine sociodemographic, vascular risk factor, and brain imaging correlates.METHODSCases of MCI and probable dementia were adjudicated by a team of neuropsychologists and neurologists and prevalence was estimated across race/ethnic groups. Ordinal proportional odds models were used to estimate race/ethnic differences in prevalence rates for MCI or probable dementia adjusting for sociodemographic variables (model 1), model 1 plus potentially modifiable vascular risk factors (model 2), and model 1 plus structural imaging markers of brain integrity (model 3).RESULTSThere were 989 participants with cognitive outcome determinations (mean age 69 ± 9 years; 68% Hispanic, 16% Black, 14% White; 62% women; mean (±SD) follow-up five (±0.6) years). Prevalence rates for MCI (20%) and probable dementia (5%) were significantly different by race/ethnicity even after accounting for age and education difference across race-ethnic groups; Hispanic and Black participants had greater prevalence rates than Whites. Adjusting for sociodemographic and brain imaging factors explained the most variance in the race/ethnicity associations. White matter hyperintensity burden explained much of the disparity between Black and White, but not between Hispanic and White, participants.CONCLUSIONSIn this diverse community-based cohort, white matter hyperintensity burden partially explained disparities in MCI and dementia prevalence in Black but not Hispanic participants compared to Whites. Longer follow-up and incidence data are needed to further clarify these relationships.

The brain signature concept aims to characterize brain regions most strongly associated with an outcome of interest. Brain signatures derive their power from data-driven searches that select features based solely on performance metrics of prediction or classification. This approach has important potential to delineate biologically relevant brain substrates for prediction or classification of future trajectories. Recent work has used exploratory voxel-wise or atlas-based searches, with some using machine learning techniques to define salient features. These have shown undoubted usefulness, but two issues remain. The preponderance of recent work has been aimed at categorical rather than continuous outcomes, and it is rare for non-atlas reliant voxel-based signatures to be reported that would be useful for modelling and hypothesis testing. We describe a cross-validated signature region model for structural brain components associated with baseline and longitudinal episodic memory across cognitively heterogeneous populations including normal, mild impairment and dementia. We used three non-overlapping cohorts of older participants: from the UC Davis Aging and Diversity cohort (n = 255; mean age 75.3 ± 7.1 years; 128 cognitively normal, 97 mild cognitive impairment, 30 demented and seven unclassified); from Alzheimer’s Disease Neuroimaging Initiative (ADNI) 1 (n = 379; mean age 75.1 ± 7.2; 82 cognitively normal, 176 mild cognitive impairment, 121 Alzheimer’s dementia); and from ADNI2/GO (n = 680; mean age 72.5 ± 7.1; 220 cognitively normal, 381 mild cognitive impairment and 79 Alzheimer’s dementia). We used voxel-wise regression analysis, correcting for multiple comparisons, to generate an array of regional masks corresponding to different association strength levels of cortical grey matter with baseline memory and brain atrophy with memory change. Cognitive measures were episodic memory using Spanish and English Neuropsychological Assessment Scales instruments for UC Davis and ADNI-Mem for ADNI 1 and ADNI2/GO. Performance metric was the adjusted R2 coefficient of determination of each model explaining outcomes in two cohorts other than where it was computed. We compared within-cohort performances of signature models against each other and against other recent signature models of episodic memory. Findings were: (i) two independently generated signature region of interest models performed similarly in a third separate cohort; (ii) a signature region of interest generated in one imaging cohort replicated its performance level when explaining cognitive outcomes in each of other, separate cohorts; and (iii) this approach better explained baseline and longitudinal memory than other recent theory-driven and data-driven models. This suggests our approach can generate signatures that may be easily and robustly applied for modelling and hypothesis testing in mixed cognition cohorts.

Objective We aimed to characterize cortical superficial siderosis, its determinants and sequel, in community-dwelling older adults. Methods The sample consisted of Framingham ( n = 1724; 2000–2009) and Rotterdam ( n = 4325; 2005–2013) study participants who underwent brain MRI. In pooled individual-level analysis, we compared baseline characteristics in patients with cortical superficial siderosis to two reference groups: (i) persons without hemorrhagic MRI markers of cerebral amyloid angiopathy (no cortical superficial siderosis and no microbleeds) and (ii) those with presumed cerebral amyloid angiopathy based on the presence of strictly lobar microbleeds but without cortical superficial siderosis. Results Among a total of 6049 participants, 4846 did not have any microbleeds or cortical superficial siderosis (80%), 401 had deep/mixed microbleeds (6.6%), 776 had strictly lobar microbleeds without cortical superficial siderosis (12.8%) and 26 had cortical superficial siderosis with/without microbleeds (0.43%). In comparison to participants without microbleeds or cortical superficial siderosis and to those with strictly lobar microbleeds but without cortical superficial siderosis, participants with cortical superficial siderosis were older (OR 1.09 per year, 95% CI 1.05, 1.14; p 999.99; p = 0.006). During a mean follow-up of 5.6 years, 42.4% participants with cortical superficial siderosis had a stroke (five intracerebral hemorrhage, two ischemic strokes and four undetermined strokes), 19.2% had transient neurological deficits and 3.8% developed incident dementia. Conclusion Our study adds supporting evidence to the association between cortical superficial siderosis and cerebral amyloid angiopathy within the general population. Community-dwelling persons with cortical superficial siderosis may be at high risk for intracerebral hemorrhage and future neurological events.

ObjectiveTo test the hypothesis that reduced slow-wave sleep, or N3 sleep, which is thought to underlie the restorative functions of sleep, is associated with MRI markers of brain aging, we evaluated this relationship in the community-based Framingham Heart Study Offspring cohort using polysomnography and brain MRI.MethodsWe studied 492 participants (age 58.8 ± 8.8 years, 49.4% male) free of neurological diseases who completed a brain MRI scan and in-home overnight polysomnography to assess slow-wave sleep (absolute duration and percentage of total sleep). Volumes of total brain, total cortical, frontal cortical, subcortical gray matter, hippocampus, and white matter hyperintensities were investigated as a percentage of intracranial volume, and the presence of covert brain infarcts was evaluated. Linear and logistic regression models were adjusted for age, age squared, sex, time interval between polysomnography and MRI (3.3 ± 1.0 years), APOE ε4 carrier status, stroke risk factors, sleeping pill use, body mass index, and depression.ResultsLess slow-wave sleep was associated with lower cortical brain volume (absolute duration, β [standard error] = 0.20 [0.08], p = 0.015; percentage, 0.16 [0.08], p = 0.044), lower subcortical brain volume (percentage, 0.03 [0.02], p = 0.034), and higher white matter hyperintensities volume (absolute duration, −0.12 [0.05], p = 0.010; percentage, −0.10 [0.04], p = 0.033). Slow-wave sleep duration was not associated with hippocampal volume or the presence of covert brain infarcts.ConclusionLoss of slow-wave sleep might facilitate accelerated brain aging, as evidence by its association with MRI markers suggestive of brain atrophy and injury. Alternatively, subtle injuries and accelerated aging might reduce the ability of the brain to produce slow-wave sleep.

Objective To compare the diagnostic accuracy of antemortem [11 C]Pittsburgh Compound B (PIB) and [18 F]Flurodeoxyglucose (FDG) positron emission tomography (PET) versus autopsy diagnosis in a heterogenous sample of patients. Methods 101 participants underwent PIB and FDG PET during life and neuropathological assessment. PET scans were visually interpreted by three raters blinded to clinical information. PIB PET was rated as positive or negative for cortical retention while FDG scans were read as showing an Alzheimer's disease (AD) or non-AD pattern. Neuropathological diagnoses were assigned using research criteria. Majority visual reads were compared to intermediate-high AD Neuropathological Changes (ADNC). Results 101 participants were included (mean age 67.2; 41 females; MMSE 21.9; PET-to-autopsy 4.4 years). At autopsy, 32 patients showed primary AD, 56 non-AD neuropathology (primarily frontotemporal lobar degeneration (FTLD)) and 13 mixed AD/FTLD pathology. PIB showed higher sensitivity than FDG for detecting intermediate-high ADNC (96% [95% confidence interval: 89-100%] vs 80% [68-92%], p=0.02), but equivalent specificity (86% [76-95%] vs. 84% [74-93%], p=0.80). In patients with congruent PIB and FDG reads (77/101), combined sensitivity was 97% [92-100%] and specificity 98% [93-100%]. Nine of 24 patients with incongruent reads were found to have co-occurrence of AD and non-AD pathologies. Interpretation In our sample enriched for younger-onset cognitive impairment, PIB-PET had higher sensitivity than FDG-PET for intermediate-high ADNC with similar specificity. When both modalities are congruent, sensitivity and specificity approach 100%, while mixed pathology should be considered when PIB and FDG are incongruent. This article is protected by copyright. All rights reserved.

Background: As Alzheimer’s disease (AD) and cerebral small vessel disease (CSVD) commonly coexist, the interaction between two has been of the considerable interest. Objective: We determined whether the association of Aβ and tau with cognitive decline differs by the presence of significant CSVD. Methods: We included 60 subcortical vascular cognitive impairment (SVCI) from Samsung Medical Center and 82 Alzheimer’s disease-related cognitive impairment (ADCI) from ADNI, who underwent Aβ (florbetaben or florbetapir) and tau (flortaucipir, FTP) PET imaging. They were retrospectively assessed for 5.0±3.9 and 5.6±1.9 years with Clinical Dementia Rating-sum of boxes (CDR-SB)/Mini-Mental State Examination (MMSE). Mixed effects models were used to investigate the interaction between Aβ/tau and group on CDR-SB/MMSE changes. Results: The frequency of Aβ positivity (45% versus 54.9%, p = 0.556) and mean global FTP SUVR (1.17±0.21 versus 1.16±0.17, p = 0.702) were not different between the two groups. We found a significant interaction effect of Aβ positivity and SVCI group on CDR-SB increase/MMSE decrease (p = 0.013/p

OBJECTIVE: The longitudinal association of blood biomarkers of total tau (t-tau), neurofilament light (Nf-L), and glial fibrillary acidic protein (GFAP) with common sporadic AD and cognitive decline are not established. METHODS: Using a single molecule array technology, ultrasensitive immunoassays for serum concentrations of total tau (t-tau), neurofilament light (Nf-L), and glial fibrillary acidic protein (GFAP) were measured in a population sample of 1,327 participants (60% African Americans and women) who had a clinical evaluation for AD, completed in-home cognitive assessments, and undergone 1.5T structural MRI. RESULTS: Higher concentrations of serum biomarkers were associated with the development of clinical AD, especially, the time-specific associations were notable: t-tau 8–16 years, and Nf-L and GFAP 4–8 years prior to clinical AD. Serum biomarkers were associated with faster cognitive decline over 16 years: baseline t-tau above 0.40 pg/mL had 30% faster decline, Nf-L above 25.5 pg/mL had 110% faster decline, and GFAP above 232 pg/mL had 130% faster decline compared to those in the lowest quartile. Participants with baseline GFAP above 232 pg/mL showed 160% faster decline in hippocampal volume compared to those below 160 pg/mL. Additionally, higher baseline t-tau was associated with faster increase in third ventricular volume, and baseline Nf-L and GFAP were associated with faster decline in cortical thickness. INTERPRETATION: Serum t-tau, Nf-L, and GFAP predict the development of sporadic AD and cognitive decline, and changes in structural brain characteristics, suggesting their usefulness not only as screening and predictive biomarkers, but also in capturing the pathogenesis of Alzheimer’s dementia.

OBJECTIVE: Examine whether cognitive reserve moderates the association of 1) vascular risk factors and 2) white matter hyperintensity burden with risk of clinical progression and longitudinal cognitive decline. METHODS: BIOCARD Study participants were cognitively normal and primarily middle-aged (M=57 years) at baseline and have been followed with annual cognitive and clinical assessments (M=13 years). Baseline cognitive reserve was indexed with a composite score combining education with reading and vocabulary scores. Baseline vascular risk (N=229) was assessed with a composite risk score reflecting five vascular risk factors. Baseline white matter hyperintensity load (N=271) was measured with FLAIR magnetic resonance imaging. Cox regression models assessed risk of progression from normal cognition to onset of clinical symptoms of Mild Cognitive Impairment. Longitudinal mixed effects models measured the relationship of these variables to cognitive decline, using a global composite score, and executive function and episodic memory sub-scores. RESULTS: Both vascular risk and white matter hyperintensities were associated with cognitive decline, particularly in executive function. Higher vascular risk, but not white matter hyperintensity burden, was associated with an increased risk of progression to Mild Cognitive Impairment. Higher cognitive reserve was associated with a reduced risk of symptom onset and higher levels of baseline cognition but did not modify the associations between the vascular risk score and white matter hyperintensities with clinical progression or cognitive decline. INTERPRETATION: Although cognitive reserve has protective effects on clinical and cognitive outcomes, it does not mitigate the negative impact of vascular risk and small vessel cerebrovascular disease on these same outcomes.

Objective Cerebral microbleeds (CMBs) are associated with higher risk of stroke and dementia, predating clinical diagnosis by several years. CMB are considered markers of cerebral small vessel disease (CSVD): hypertensive (deep CMB) and cerebral amyloid angiopathy (lobar CMB). We related plasma β‐Amyloid (40, 42 and their ratio), clusterin, and tau levels to CMB to elucidate their role as biomarkers for the angiopathies represented by CMB. Methods Dementia, stroke, and other neurological disease‐free Framingham Heart Study participants with available CMB and biomarker measurements were included. We related biomarker levels (standardized for analyses) to CMB presence overall and stratified by brain topography (any, lobar, deep), using multivariable logistic regression analyses. Results CMB were observed in 208 (5.7%) participants (mean age 57 years, 54% women). After multivariable adjustment, Aβ1‐40 was associated with any CMB (OR (95%CI) 1.20 (0.99, 1.45) P = 0.062)) and lobar CMB (OR (95%CI) 1.33 (1.05, 1.68) P = 0.019), but not with deep CMB. Log‐Aβ1‐42 levels were not associated with CMB overall. Clusterin was related to mixed CMB (1.70 [1.05, 2.74], P = 0.031). Tau levels were associated with any CMB (OR (95%CI) 1.26 (1.07, 1.49) P = 0.006), lobar CMB (OR (95%CI) 1.26 (1.05, 1.52) P = 0.013), and with deep CMB (OR (95% CI) 1.46 (1.13, 1.89) P = 0.004). Interpretation We found that plasma Aβ1‐40 and Tau are associated with CMB but further studies are needed to confirm their role in hemorrhage prone CSVD represented by CMB and as indicators of ongoing subclinical neuronal injury.

Introduction We investigated plasma proteomic markers of astrocytopathy, brain degeneration, plasticity, and inflammation in sporadic early-onset versus late-onset Alzheimer's disease (EOAD and LOAD). Methods Plasma was analyzed using ultra-sensitive immuno-based assays from 33 EOAD, 30 LOAD, and 36 functionally normal older adults. Results Principle component analyses identified 3 factors: trophic (BDNF, VEGF, TGFβ), degenerative (GFAP, NfL), and inflammatory (TNFα, IL-6, IP-10, IL-10). Trophic factor was elevated in both AD groups and associated with cognition and gray matter volumes. Degenerative factor was elevated in EOAD, with higher levels associated with worse functioning in this group. Biomarkers of inflammation were not significantly different between groups and were only associated with age. Disucssion Plasma proteomic biomarkers provide novel means of investigating molecular processes in vivo and their contributions to clinical outcomes. We present initial investigations of several of these fluid biomarkers, capturing aspects of astrocytopathy, neuronal injury, cellular plasticity, and inflammation in EOAD versus LOAD.

BACKGROUND: We determined the association between ratios of plasma ceramide species of differing fatty-acyl chain lengths and incident dementia and Alzheimers disease (AD) dementia in a large, community-based sample. METHODS: We measured plasma ceramide levels in 1892 [54% women, mean age 70.1 (SD 6.9) yr.] dementia-free Framingham Offspring Study cohort participants between 2005 and 2008. We related ratios of very long-chain (C24:0, C22:0) to long-chain (C16:0) ceramides to subsequent risk of incident dementia and AD dementia. Structural MRI brain measures were included as secondary outcomes. RESULTS: During a median 6.5year follow-up, 81 participants developed dementia, of whom 60 were diagnosed with AD dementia. In multivariable Cox-proportional hazards analyses, each standard deviation (SD) increment in the ratio of ceramides C24:0/C16:0 was associated with a 27% reduction in the risk of dementia (HR 0.73, 95% CI 0.56-0.96) and AD dementia (HR 0.73, 95% CI 0.53-1.00). The ratio of ceramides C22:0/C16:0 was also inversely associated with incident dementia (HR per SD 0.75, 95% CI 0.57-0.98), and approached statistical significance for AD (HR 0.73, 95% CI 0.53-1.01, P=0.056). Higher ratios of ceramides C24:0/C16:0 and C22:0/C16:0 were also cross-sectionally associated with lower white matter hyperintensity burden on MRI (-0.05±0.02, P=0.02; -0.06±0.02, P=0.003; respectively per SD increase), but not with other MRI brain measures. CONCLUSIONS: Higher plasma ratios of very long-chain to long-chain ceramides are associated with a reduced risk of incident dementia and AD dementia in our community-based sample. Circulating ceramide ratios may serve as potential biomarkers for predicting dementia risk in cognitively healthy adults.

ObjectiveRecent studies suggest that white matter hyperintensities (WMH) on MRI, which primarily reflect small vessel cerebrovascular disease, may play a role in the evolution of Alzheimer disease (AD). In a longitudinal study, we investigated whether WMH promote the progression of AD pathology, or alter the association between AD pathology and risk of progression from normal cognition to mild cognitive impairment (MCI).MethodsTwo sets of analyses were conducted. The relationship between whole brain WMH load, based on fluid-attenuated inversion recovery MRI, obtained in initially cognitively normal participants (n = 274) and time to onset of symptoms of MCI (n = 60) was examined using Cox regression models. In a subset of the participants with both MRI and CSF data (n = 204), the interaction of WMH load and CSF AD biomarkers was also evaluated.ResultsBaseline WMH load interacted with CSF total tau (t-tau) with respect to symptom onset, but not with CSF β-amyloid 1–42 or phosphorylated tau (p-tau) 181. WMH volume was associated with time to symptom onset of MCI among individuals with low t-tau (hazard ratio [HR] 1.35, confidence interval [CI] 1.06–1.73, p = 0.013), but not those with high t-tau (HR 0.86, CI 0.56–1.32, p = 0.47). The rate of change in the CSF biomarkers over time was not associated with the rate of change in WMH volumes.ConclusionThese results suggest that WMH primarily affect the risk of progression when CSF measures of neurodegeneration or neuronal injury (as reflected by t-tau) are low. However, CSF biomarkers of amyloid and p-tau and WMH appear to have largely independent and nonsynergistic effects on the risk of progression to MCI.

Combining datasets from multiple sites/scanners has been becoming increasingly more prevalent in modern neuroimaging studies. Despite numerous benefits from the growth in sample size, substantial technical variability associated with site/scanner-related effects exists which may inadvertently bias subsequent downstream analyses. Such a challenge calls for a data harmonization procedure which reduces the scanner effects and allows the scans to be combined for pooled analyses. In this work, we present MISPEL (Multi-scanner Image harmonization via Structure Preserving Embedding Learning), a multi-scanner harmonization framework. Unlike existing techniques, MISPEL does not assume a perfect coregistration across the scans, and the framework is naturally extendable to more than two scanners. Importantly, we incorporate our multi-scanner dataset where each subject is scanned on four different scanners. This unique paired dataset allows us to define and aim for an ideal harmonization (e.g., each subject with identical brain tissue volumes on all scanners). We extensively view scanner effects under varying metrics and demonstrate how MISPEL significantly improves them.

Purpose: To quantitatively investigate the microstructural properties of the optic nerve (ON) in vivo using diffusion magnetic resonance imaging (dMRI) tractography in an elderly population and to determine the differences between the ON diffusion properties stratified by basic demographics.Methods: We measured fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) of the intraorbital ON in cognitively normal controls selected from the Alzheimer's Disease Neuroimaging Initiative 3 database (n =104; mean age = 73. 8 ± 8.1 years) using dMRI probabilistic tractography and evaluated the correlation between diffusion parameters and demographic factors. Diffusion parameters were measured in 20 equidistant nodes along the tract, and the data from proximal 70% (14 nodes) of the intraorbital ON were averaged.Results: The mean FA of the intraorbital ON was 0.392 ± 0.063, and the mean MD was 1.163 ± 0.165 μm2/s. The mean RD was 0.882 ± 0.152 μm2/s, and the mean AD was 1.693 ± 0.183 μm2/s. The multiple linear regression model showed a negative correlation between FA and age. FA in females was significantly higher than males, whereas RD in female was significantly lower.Conclusions: We measured the diffusion properties of the intraorbital ON using dMRI tractography in an elderly cognitively normal population. The diffusion properties detected by dMRI tractography may substantially reflect the microstructure of the ON.

Cognitive decline is common in chronic kidney disease (CKD). While the evidence of vascular cognitive impairment in this population is robust, the role of Alzheimer's pathology is unknown. We evaluated serum cystatin C-estimated glomerular filtration rate (eGFR), brain amyloid-β positron emission tomography (PET) imaging, and cognitive function in 166 participants from The 90+ Study. Mean age was 93 years (range 90-107) and 101 (61%) were women; 107 participants had normal cognitive status while 59 participants had cognitive impairment no dementia (CIND) or dementia. Mean ± standard deviation cystatin C was 1.59 ± 0.54 mg/L with eGFR 40.7 ± 18.7 ml/min/1.73m2. Higher amyloid-β burden was associated with dementia, but not with age, diabetes, hypertension, or cardiovascular disease. We found no association between brain amyloid-β burden and cystatin C eGFR. We previously reported that kidney function was associated with cognition and cerebral microbleeds in the same cohort of oldest-old adults (90+ years old). Collectively, these findings suggest that microvascular rather than Alzheimer's pathology drives CKD-associated cognitive dysfunction in this population.

Background: Using magnetic resonance diffusion tensor imaging, we previously showed a cross-sectional association between carotid-femoral pulse wave velocity, a measure of aortic stiffness, and subtle white matter injury in clinically asymptomatic middle-age adults. While coronary artery calcium (CAC) is a robust measure of atherosclerosis, and a predictor of stroke and dementia, whether it predicts diffusion tensor imaging-based subtle white matter injury in the brain remains unknown. Methods: In FHS (Framingham Heart Study), an observational study, third-generation participants were assessed for CAC (2002–2005) and brain magnetic resonance imaging (2009–2014). Outcomes were diffusion tensor imaging-based measures; free water, fractional anisotropy, and peak width of mean diffusivity. After excluding the participants with neurological conditions and missing covariates, we categorized participants into 3 groups according to CAC score (0, 0 < to 100, and >100) and calculated a linear trend across the CAC groups. In secondary analyses treating CAC score as continuous, we computed slope of the outcomes per 20 to 80th percentiles higher log-transformed CAC score using linear regression. Results: In a total of 1052 individuals analyzed (mean age 45.4 years, 45.4% women), 71.6%, 22.4%, and 6.0% had CAC score of 0, 0 < to 100, and >100, respectively. We observed a significant linear trend of fractional anisotropy, but not other measures, across the CAC groups after multivariable adjustment. In the secondary analyses, CAC was associated with lower fractional anisotropy in men but not in women. Conclusions: CAC may be a promising tool to predict prevalent subtle white matter injury of the brain in asymptomatic middle-aged men.

Background and purpose There is limited literature on the prevalence of incidental brain MRI findings in the Hispanic/Latino population, despite their increased prevalence of vascular disease and undertreatment of chronic conditions. The purpose of our study was to determine the prevalence of clinically relevant incidental findings on brain MRI examinations obtained as a part of the Study of Latinos-Investigation of NeuroCognitive Aging MRI (SOL-INCA-MRI) study. Methods Brain MRI examinations were obtained on 1389 participants in the SOL-INCA-MRI study, a cross-sectional ancillary study of the Hispanic Community Health Study, Study of Latinos, which is a longitudinal, community-based study. Study design of SOL-INCA-MRI involves imaging cognitively normal and participants with mild cognitive impairment. Brain MRI findings were categorized as Level 1 (normal), Level 1.5 (findings of unclear medical significance), Level 2 (potential medical concern), or Level 3 (medically urgent). This article focuses on Level 2 and Level 3 findings. Results The average age of the sample was 60.8 years (+/- 10.3 years), 66.1% were females. Level 2 and 3 findings were identified in 117 participants, (8.4%), of which 109 (7.8%) were recommended for medical follow-up (Level 2), and 8 (0.6%) were recommended for immediate medical attention (Level 3). Brain MRI findings consisted of chronic infarction in 33 (2.4%), vascular abnormality in 27 (1.9%), intracranial mass in 20 (1.4%), other intracranial findings in 28 (2.0%), and skull base/extracranial findings in 26 (1.9%) patients. Conclusion Incidental findings of clinical relevance were common among SOL-INCA-MRI participants, but rarely required urgent medical intervention.

INTRODUCTIONBlood metabolomics-based biomarkers may be useful to predict measures of neurocognitive aging.METHODSWe tested the association between 707 blood metabolites measured in 1,451 participants from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), with MCI and global cognitive change assessed seven years later. We further used Lasso penalized regression to construct a metabolomics risk score (MRS) that predicts MCI, potentially identifying a different set of metabolites than those discovered in individual-metabolite analysis.RESULTSWe identified 20 metabolites associated with MCI and/or global cognitive change. Six of them were novel and 14 were previously reported as associated with neurocognitive aging outcomes. The MCI MRS comprised 61 metabolites and improved prediction accuracy from 84% (minimally adjusted model) to 89% in the entire dataset and from 75% to 87% among APOE-ε4 carriers.DISCUSSIONBlood metabolites may serve as biomarkers identifying individuals at risk for MCI among U.S. Hispanics/Latinos.

Background: Adherence to the Mediterranean-DASH for Neurodegenerative Delay (MIND) diet has previously been associated with cognitive decline and dementia. To our knowledge, no prior study has investigated the association between the MIND diet and measures of brain volume, silent brain infarcts (SBIs), or brain atrophy. Objective: We evaluated whether adherence to the MIND diet associated with superior cognitive function, larger brain volumes, fewer SBIs, and less cognitive decline in the community-based Framingham Heart Study. Methods: 2,092 participants (mean±SD, age 61±9) completed Food Frequency Questionnaires, averaged across a maximum of 3-time points (examination cycles 5, 6, and 7), cognitive testing at examination cycle 7 (present study baseline: 1998–2001) and after a mean±SD of 6.6±1.1 years from baseline (n = 1,584). A subset of participants also completed brain magnetic resonance imaging (MRI) at examination cycle 7 (n = 1,904). In addition, participants with dementia, stroke, and other relevant neurological diseases such as significant head trauma, subdural hematoma, or multiple sclerosis were excluded from the analyses. Results: Higher MIND diet scores were associated with better global cognitive function (β±SE,+0.03SD±0.01; p = 0.004), verbal memory, visual memory, processing speed, verbal comprehension/reasoning, and with larger total brain volume (TBV) following adjustments for clinical, lifestyle and demographic covariates, but not with other brain MRI measures (i.e., hippocampal volume, lateral ventricular volume, white matter hyperintensity volume, and SBIs) or cognitive decline. Conclusion: Higher MIND diet scores associated with better cognitive performance and larger TBV at baseline, but not with cognitive decline. Clinical trials are needed to ascertain whether adopting the MIND diet affects trajectories of cognitive decline.

Deep learning implementations using convolutional neural nets have recently demonstrated promise in many areas of medical imaging. In this article we lay out the methods by which we have achieved consistently high quality, high throughput computation of intra-cranial segmentation from whole head magnetic resonance images, an essential but typically time-consuming bottleneck for brain image analysis. We refer to this output as “production-level” because it is suitable for routine use in processing pipelines. Training and testing with an extremely large archive of structural images, our segmentation algorithm performs uniformly well over a wide variety of separate national imaging cohorts, giving Dice metric scores exceeding those of other recent deep learning brain extractions. We describe the components involved to achieve this performance, including size, variety and quality of ground truth, and appropriate neural net architecture. We demonstrate the crucial role of appropriately large and varied datasets, suggesting a less prominent role for algorithm development beyond a threshold of capability.

Introduction We estimated the prevalence and correlates of mild cognitive impairment (MCI) among middle-aged and older diverse Hispanics/Latinos. Methods Middle-aged and older diverse Hispanics/Latinos enrolled (n = 6377; 50–86 years) in this multisite prospective cohort study were evaluated for MCI using the National Institute on Aging–Alzheimer's Association diagnostic criteria. Results The overall MCI prevalence was 9.8%, which varied between Hispanic/Latino groups. Older age, high cardiovascular disease (CVD) risk, and elevated depressive symptoms were significant correlates of MCI prevalence. Apolipoprotein E4 (APOE) and APOE2 were not significantly associated with MCI. Discussion MCI prevalence varied among Hispanic/Latino backgrounds, but not as widely as reported in the previous studies. CVD risk and depressive symptoms were associated with increased MCI, whereas APOE4 was not, suggesting alternative etiologies for MCI among diverse Hispanics/Latinos. Our findings suggest that mitigating CVD risk factors may offer important pathways to understanding and reducing MCI and possibly dementia among diverse Hispanics/Latinos.

OBJECTIVE: A rare variant in TREM2 (p.R47H, rs75932628) has been consistently reported to increase the risk for Alzheimer’s disease, while mixed evidence has been reported for association of the variant with other neurodegenerative diseases. Here, we investigated the frequency of the R47H variant in a diverse and well-characterized multicenter neurodegenerative disease cohort. METHODS: We examined the frequency of the R47H variant in a diverse neurodegenerative disease cohort, including a total of 3,058 patients clinically diagnosed with Alzheimer’s disease, frontotemporal dementia spectrum syndromes, mild cognitive impairment, progressive supranuclear palsy syndrome, corticobasal syndrome, or amyotrophic lateral sclerosis and 5,089 control subjects. RESULTS: We observed a significant association between the R47H variant and Alzheimer’s disease, while no association was observed with any other neurodegenerative disease included in this study. CONCLUSIONS: Our results support the consensus that the R47H variant is significantly associated with Alzheimer’s disease. However, we did not find evidence for association of the R47H variant with other neurodegenerative diseases.

To apply an AT (Aβ/tau) classification system to subcortical vascular cognitive impairment (SVCI) patients following recently developed biomarker-based criteria of Alzheimer’s disease (AD), and to investigate its clinical significance. We recruited 60 SVCI patients who underwent the neuropsychological tests, brain MRI, and 18F-florbetaben and 18F-AV1451 PET at baseline. As a control group, we further recruited 27 patients with AD cognitive impairment (ADCI; eight Aβ PET-positive AD dementia and 19 amnestic mild cognitive impairment). ADCI and SVCI patients were classified as having normal or abnormal Aβ (A−/A+) and tau (T−/T+) based on PET results. Across the three SVCI groups (A−, A+T−, and A+T+SVCI), we compared longitudinal changes in cognition, hippocampal volume (HV), and cortical thickness using linear mixed models. Among SVCI patients, 33 (55%), 20 (33.3%), and seven (11.7%) patients were A−, A+T−, and A+T+, respectively. The frequency of T+ was lower in A+SVCI (7/27, 25.9%) than in A+ADCI (14/20, 70.0%, p = 0.003) which suggested that cerebral small vessel disease affected cognitive impairments independently of A+. A+T−SVCI had steeper cognitive decline than A−SVCI. A+T+SVCI also showed steeper cognitive decline than A+T−SVCI. Also, A+T−SVCI had steeper decrease in HV than A−SVCI, while cortical thinning did not differ between the two groups. A+T+SVCI had greater global cortical thinning compared with A+T−SVCI, while declines in HV did not differ between the two groups. This study showed that the AT system successfully characterized SVCI patients, suggesting that the AT system may be usefully applied in a research framework for clinically diagnosed SVCI.

Higher plasma total-tau level is associated with incident dementia, but its relationship with stroke risk is unknown. In this prospective community-based study, we evaluated plasma total-tau level as a biomarker of stroke risk in 2,794 Framingham Heart Study participants. Persons with plasma total-tau levels in the top quintile, versus the bottom 4, had an increased risk of incident stroke over a mean follow-up of 8.3 years (hazard ratio = 2.01; 95% confidence interval = 1.32-3.08) following adjustments for age, sex, and stroke risk factors. Our findings demonstrate that plasma total-tau relates to the risk of stroke in a community sample. ANN NEUROL 2019;86:463-467.

ObjectiveTo examine associations between measures of obesity in middle to early-old age with later-life MRI markers of brain aging.MethodsWe analyzed data from the Northern Manhattan MRI Sub-Study (n = 1,289). Our exposures of interest were body mass index (BMI), waist circumference (WC), waist-to-hip ratio, and plasma adiponectin levels. Our outcomes of interest were total cerebral volume (TCV), cortical thickness, white matter hyperintensity volume (WMHV), and subclinical brain infarcts (SBI). Using multivariable linear and logistic regression models adjusted for sociodemographics, health behaviors, and vascular risk factors, we estimated β coefficients (or odds ratios) and 95% confidence intervals (CIs) and tested interactions with age, sex, and race/ethnicity.ResultsOn average at baseline, participants were aged 64 years and had 10 years of education; 60% were women and 66% were Caribbean Hispanic. The mean (SD) time lag between baseline and MRI was 6 (3) years. Greater BMI and WC were significantly associated with thinner cortices (BMI β [95% CI] −0.089 [−0.153, −0.025], WC β [95% CI] −0.103 [−0.169, −0.037]) in fully adjusted models. Similarly, compared to those with BMI ConclusionsAdiposity in early-old age is related to reduced global gray matter later in life in this diverse sample. Future studies are warranted to elucidate causal relationships and explore region-specific associations.

Our nation is becoming increasingly diverse; however, few autopsy studies examine multiple ethnoracial groups, especially Hispanics. We examined differences in neuropathological diagnoses of 423 deceased participants with dementia from three ethnoracial groups (35 Black, 28 Hispanic, and 360 non-Hispanic White) evaluated at the University of California Davis Alzheimer's Disease Center. We used novel applications of bootstrap resampling and logistic regression standardization to project neuropathological diagnostic rates for non-Hispanic Whites to minority sample characteristics to improve inference of findings. Alzheimer's disease (AD) without significant cerebrovascular disease (CVD) or other dementia-related pathologies (AD (non-mixed)) was present in 15 Black (43%), 4 Hispanic (14%), and 156 (43%) non-Hispanic Whites. CVD sufficient to contribute to dementia was confirmed in 14 Black (40%), 15 Hispanic (54%), and 101 (28%) non-Hispanic White decedents. The observed CVD prevalence of 40% in Blacks exceeded the predicted 29% [95% CI: 22%-36%]. Despite being outside the 95% confidence interval, the difference between observed and predicted was not statistically significant after bootstrap testing. Conversely, for Hispanics, the observed proportion at 54% exceeded significantly the predicted prevalence of 24% from non-Hispanic Whites [95% CI: 16%-34%], avg. p = 0.008). An identical analysis using AD (non-mixed) as the outcome predicted AD (non-mixed) in Blacks averaging 41% [95% CI: 34%-48%], nearly equal to observed prevalence. For Hispanics, however, the observed proportion at 14%, was well below predictions (mean = 42%, 95% CI: 32%-53%], avg. p = 0.008). We conclude mixed diagnoses and CVD are more common in Hispanic and Black decedents than Non-Hispanic Whites with dementia in our cohort. The increased prevalence of vascular co-morbidity may be a potential opportunity to intervene more effectively in dementia treatment of those individuals.

ObjectiveWe investigated differences in the anatomical distribution of cerebral microbleeds (CMBs) on MRI, hypothesized to indicate the type of underlying cerebral small vessel disease (SVD), between Eastern and Western general populations.MethodsWe analyzed data from 11 studies identified by a PubMed search between 1996 and April 2014 according to the Preferred Reporting Items for a Systematic Review and Meta-analysis of Individual Participant Data. Study quality measures indicated low or medium risk of bias. We included stroke-free participants from populations aged between 55 and 75 years, categorized by geographic location (Eastern or Western). We categorized CMB distribution (strictly lobar, deep and/or infratentorial [D/I], or mixed [i.e., CMBs located in both lobar and D/I regions]). We tested the hypothesis that Eastern and Western populations have different anatomical distributions of CMBs using multivariable mixed effects logistic regression analyses adjusted for age, sex, and hypertension and clustering by institution.ResultsAmong 8,595 stroke-free individuals (mean age [SD] 66.7 [5.6] years; 48% male; 42% from a Western population), 624 (7.3%) had CMBs (strictly lobar in 3.1%; D/I or mixed in 4.2%). In multivariable mixed effects models, Eastern populations had higher odds of D/I or mixed CMBs (adjusted odds ratio 2.78, 95% confidence interval [CI] 1.77–4.35) compared to Western populations. Eastern populations had a higher number of D/I or mixed CMBs (adjusted prevalence ratio 2.83, 95% CI 1.27–6.31).ConclusionsEastern and Western general populations have different anatomical distributions of CMBs, suggesting differences in the spectrum of predominant underlying SVDs, with potential implications for SVD diagnosis and treatment.

The research was supported by the Alzheimer’s Society (grant numbers AS-PG-2013-011 and AS-JF-18-01). Tissue for this study was provided by the Newcastle Brain Tissue Resource, which is funded in part by a grant from the UK Medical Research Council (G0400074) and by Brains for Dementia research, a joint venture between Alzheimer’s Society and Alzheimer’s Research UK. The blood‐brain barrier (BBB) regulates cerebrovascular permeability and leakage of blood‐derived fibrinogen has been associated with cerebral arteriolosclerosis small vessel disease (SVD) and subsequent white matter lesions (WML). Furthermore, BBB‐dysfunction is associated with the pathogenesis of Alzheimer's disease (AD) with the presence of CSF plasma proteins suggested to be a potential biomarker of AD. We aimed to determine if extravascular fibrinogen in the white matter was associated with the development of AD hallmark pathologies, i.e., hyperphosphorylated tau (HPτ) and amyloid‐β (Aβ), SVD, cerebral amyloid angiopathy (CAA) and measures of white matter damage. Using human post‐mortem brains, parietal tissue from 20 AD and 22 non‐demented controls was quantitatively assessed for HPτ, Aβ, white matter damage severity, axonal density, demyelination and the burden of extravascular fibrinogen in both WML and normal appearing white matter (NAWM). SVD severity was determined by calculating sclerotic indices. WML‐ and NAWM fibrinogen burden was not significantly different between AD and controls nor was it associated with the burden of HPτ or Aβ pathology, or any measures of white matter damage. Increasing severity of SVD was associated with and a predictor (both p < 0.05) of both higher WML‐ and NAWM fibrinogen burden (both P

Importance Birth in areas with high infant mortality rates (IMRs) has been linked to worse long-term health outcomes, yet it is completely unknown if it impacts dementia risk. Methods In total 6268 health care members were followed for dementia diagnosis from 1996 to 2015. Birth state IMRs from 1928 were ranked into quartile (worst IMRs quartile range, whites: 69 to 129 deaths/1000 live births, Non-whites: 129 to 277 deaths/1000 live births). Cox proportional hazard models estimated the dementia risk associated with birth state IMR quartile adjusting for demographics and lifecourse health indicators. Results Compared with whites born outside of states in the worst IMR quartile, African Americans born in states in the worst IMR quartile had 92% increased dementia risk (HR=1.92; 95% CI: 1.42, 2.59), and African Americans born outside those states had 36% increased risk (HR=1.36; 95% CI: 1.20, 1.53). There was no association between birth state IMR and dementia risk among whites. Conclusions Birth in states with the highest rates of infant mortality was associated with elevated dementia risk among African Americans but not whites. The large absolute difference in IMRs likely reflects harsher early childhood conditions experienced by African Americans. These findings suggest that childhood conditions may play a role in racial disparities in dementia rates.

Purpose We examined the association of Stroke Belt birth state with late-life cognition in The Study of Healthy Aging in African Americans (STAR). Methods STAR enrolled 764 Black Americans ages 50+ who were long-term Kaiser Permanente Northern California members. Participants completed Multiphasic Health Check-ups (MHC; 1964–1985) where early-life overweight/obesity, hypertension, diabetes, and hyperlipidemia were measured. At STAR (2018), birth state, self-reported early-life socioeconomic status (SES), and executive function, verbal episodic memory, and semantic memory scores were collected. We used linear regression to examine the association between Stroke Belt birth and late-life cognition adjusting for birth year, gender, and parental education. We evaluated early-life SES and cardiovascular risk factors (CVRF) as potential mechanisms. Results Twenty-seven percent of participants were born in the Stroke Belt with a mean age of 69 (standard deviation = 9) at STAR. Stroke Belt birth was associated with worse late-life executive function (β [95% confidence interval]: −0.18 [−0.33, −0.02]) and semantic memory (−0.37 [−0.53, −0.21]), but not verbal episodic memory (−0.04 [−0.20, 0.12]). Adjustment for SES and CVRF attenuated associations of Stroke Belt birth with cognition (executive function [−0.05 {−0.25, 0.14}]; semantic memory [−0.28 {−0.49, −0.07}]). Conclusions Black Americans born in the Stroke Belt had worse late-life cognition than those born elsewhere, underscoring the importance of early-life exposures on brain health.

The MarkVCID consortium was formed under cooperative agreements with the National Institute of Neurologic Diseases and Stroke (NINDS) and National Institute on Aging (NIA) in 2016 with the goals of developing and validating biomarkers for the cerebral small vessel diseases associated with the vascular contributions to cognitive impairment and dementia (VCID). Rigorously validated biomarkers have consistently been identified as crucial for multicenter studies to identify effective strategies to prevent and treat VCID, specifically to detect increased VCID risk, diagnose the presence of small vessel disease and its subtypes, assess prognosis for disease progression or response to treatment, demonstrate target engagement or mechanism of action for candidate interventions, and monitor disease progression during treatment. The seven project sites and central coordinating center comprising MarkVCID, working with NINDS and NIA, identified a panel of 11 candidate fluid- and neuroimaging-based biomarker kits and established harmonized multicenter study protocols (see companion paper "MarkVCID cerebral small vessel consortium: I. Enrollment, clinical, fluid protocols" for full details). Here we describe the MarkVCID neuroimaging protocols with specific focus on validating their application to future multicenter trials. MarkVCID procedures for participant enrollment; clinical and cognitive evaluation; and collection, handling, and instrumental validation of fluid samples are described in detail in a companion paper. Magnetic resonance imaging (MRI) has long served as the neuroimaging modality of choice for cerebral small vessel disease and VCID because of its sensitivity to a wide range of brain properties, including small structural lesions, connectivity, and cerebrovascular physiology. Despite MRI's widespread use in the VCID field, there have been relatively scant data validating the repeatability and reproducibility of MRI-based biomarkers across raters, scanner types, and time intervals (collectively defined as instrumental validity). The MRI protocols described here address the core MRI sequences for assessing cerebral small vessel disease in future research studies, specific sequence parameters for use across various research scanner types, and rigorous procedures for determining instrumental validity. Another candidate neuroimaging modality considered by MarkVCID is optical coherence tomography angiography (OCTA), a non-invasive technique for directly visualizing retinal capillaries as a marker of the cerebral capillaries. OCTA has theoretical promise as a unique opportunity to visualize small vessels derived from the cerebral circulation, but at a considerably earlier stage of development than MRI. The additional OCTA protocols described here address procedures for determining OCTA instrumental validity, evaluating sources of variability such as pupil dilation, and handling data to maintain participant privacy. MRI protocol and instrumental validation The core sequences selected for the MarkVCID MRI protocol are three-dimensional T1-weighted multi-echo magnetization-prepared rapid-acquisition-of-gradient-echo (ME-MPRAGE), three-dimensional T2-weighted fast spin echo fluid-attenuated-inversion-recovery (FLAIR), two-dimensional diffusion-weighted spin-echo echo-planar imaging (DWI), three-dimensional T2*-weighted multi-echo gradient echo (3D-GRE), three-dimensional T2 -weighted fast spin-echo imaging (T2w), and two-dimensional T2*-weighted gradient echo echo-planar blood-oxygenation-level-dependent imaging with brief periods of CO2 inhalation (BOLD-CVR). Harmonized parameters for each of these core sequences were developed for four 3 Tesla MRI scanner models in widespread use at academic medical centers. MarkVCID project sites are trained and certified for their instantiation of the consortium MRI protocols. Sites are required to perform image quality checks every 2 months using the Alzheimer's Disease Neuroimaging Initiative phantom. Instrumental validation for MarkVCID MRI-based biomarkers is operationally defined as inter-rater reliability, test-retest repeatability, and inter-scanner reproducibility. Assessments of these instrumental properties are performed on individuals representing a range of cerebral small vessel disease from mild to severe. Inter-rater reliability is determined by distribution of an independent dataset of MRI scans to each analysis site. Test-retest repeatability is determined by repeat MRI scans performed on individual participants on a single MRI scanner after a short (1- to 14-day) interval. Inter-scanner reproducibility is determined by repeat MRI scans performed on individuals performed across four MRI scanner models. OCTA protocol and instrumental validation The MarkVCID OCTA protocol uses a commercially available, Food and Drug Administration-approved OCTA apparatus. Imaging is performed on one dilated and one undilated eye to assess the need for dilation. Scans are performed in quadruplicate. MarkVCID project sites participating in OCTA validation are trained and certified by this biomarker's lead investigator. Inter-rater reliability for OCTA is assessed by distribution of OCTA datasets to each analysis site. Test-retest repeatability is assessed by repeat OCTA imaging on individuals on the same day as their baseline OCTA and a different-day repeat session after a short (1- to 14-day) interval. Methods were developed to allow the OCTA data to be de-identified by the sites before transmission to the central data management system. The MarkVCID neuroimaging protocols, like the other MarkVCID procedures, are designed to allow translation to multicenter trials and as a template for outside groups to generate directly comparable neuroimaging data. The MarkVCID neuroimaging protocols are available to the biomedical community and intended to be shared. In addition to the instrumental validation procedures described here, each of the neuroimaging MarkVCID kits will undergo biological validation to determine its ability to measure important aspects of VCID such as cognitive function. The analytic methods for the neuroimaging-based kits and the results of these validation studies will be published separately. The results will ultimately determine the neuroimaging kits' potential usefulness for multicenter interventional trials in small vessel disease-related VCID.

Background Midlife cardiovascular risk factors (CVRFs) increase risk of dementia. Black Americans experience an elevated prevalence of CVRFs and dementia. However, little is known of how CVRFs prior to midlife affect late-life cognition. We examined CVRFs in adolescence, young adulthood, and midlife with late-life cognition in the Study of Healthy Aging in African Americans (STAR). Method STAR assesses cognitive aging among 764 Black Americans aged ≥50 (mean age = 69; SD = 9; range = 53–95). Participants’ body mass index, blood pressure, glucose, and total cholesterol were collected during Multiphasic Health Checkups (MHC; 1964–1985). At STAR baseline (2018–2019), executive function, verbal episodic memory, and semantic memory were measured using the Spanish and English Neuropsychological Assessment Scales. Linear regression models examined associations between CVRFs and cognition adjusting for demographics and years since MHC. Results At MHC, 36% of participants had 1 CVRF and 26% had ≥2. Twenty-two percent of participants were adolescents (age 12–20), 62% young adults (age 21–34), and 16% midlife adults (age 35–56). Overweight/obesity was not associated with cognition. Hypertension was associated with worse executive function (β [95% CI]: −0.14 [−0.28, −0.0003]) and verbal episodic memory (β [95% CI]: −0.22 [−0.37, −0.07]) compared to normotension. Diabetes was associated with worse executive function (β [95% CI]: −0.43 [−0.83, −0.03]). Having ≥2 CVRFs (vs 0) was associated with worse executive function (β [95% CI]: −0.19 [−0.34, −0.03]) and verbal episodic memory (β [95% CI]: −0.25 [−0.41, −0.08]). Adolescents with hypertension had lower late-life executive function compared to normotensive adolescents (β [95% CI]: −0.39 [−0.67, −0.11]). Young adulthood hypertension (β [95% CI]: −0.29 [−0.49, −0.09]) and midlife hyperlipidemia (β [95% CI]: −0.386 [−0.70, −0.02]) were associated with lower verbal episodic memory. Conclusions Among Black Americans, life-course CVRFs were associated with poorer executive function and verbal episodic memory emphasizing the importance of cardiovascular health on the aging brain.

Advances in molecular positron emission tomography (PET) have enabled anatomic tracking of brain pathology in longitudinal studies of normal aging and dementia, including assessment of the central model of Alzheimer's disease (AD) pathogenesis, according to which TAU pathology begins focally but expands catastrophically under the influence of amyloid-beta (A beta) pathology to mediate neurodegeneration and cognitive decline. Initial TAU deposition occurs many years before A beta in a specific area of the medial temporal lobe. Building on recent work that enabled focus of molecular PET measurements on specific TAU-vulnerable convolutional temporal lobe anatomy, we applied an automated anatomic sampling method to quantify TAU PET signal in 443 adult participants from several observational studies of aging and AD, spanning a wide range of ages, A beta burdens, and degrees of clinical impairment. We detected initial cortical emergence of tauopathy near the rhinal sulcus in clinically normal people and, in a subset with longitudinal 2-year follow-up data (n = 104), tracked A beta-associated spread of TAU from this site first to nearby neocortex of the temporal lobe and then to extratemporal regions. Greater rate of TAU spread was associated with baseline measures of both global A beta burden and medial temporal lobe TAU. These findings are consistent with clinicopathological correlation studies of Alzheimer's tauopathy and enable precise tracking of AD-related TAU progression for natural history studies and prevention therapeutic trials.

IntroductionPolygenic Risk Score (PRS) are powerful summaries of genetic risk alleles that can potentially be used to predict disease outcomes and guide treatment decisions. Hispanics/Latinos suffer from higher rates of Alzheimer’s Disease (AD) and Mild Cognitive Impairment (MCI) compared to non-Hispanic Whites, yet the strongest known genetic risk factor for AD, APOE-ϵ4 allele, has weak association with AD in Hispanics/Latinos. We evaluated PRS constructed based on Genome-Wide Association Studies (GWAS) of AD in predicting MCI in Hispanics/Latinos when accounting for APOE alleles and variants.MethodsWe used summary statistics from four GWAS of AD to construct PRS that predict MCI in 4,189 diverse Hispanics/Latinos (mean age 63 years, 47% males) from the Study of Latinos-Investigation of Neurocognitive Aging. We assessed the PRS associations with MCI in the combined set of people and in groups defined by genetic ancestry and Hispanic/Latino background, and when including and excluding single nucleotide polymorphisms (SNPs) from the APOE gene region.ResultsA PRS constructed based on GWAS of AD in the FINNGEN Biobank was associated with MCI (OR = 1.34, 95% CI [1.15, 1.55]), and its association was mostly driven by 158 APOE region SNPs. A PRS constructed based on a multi-ethnic AD GWAS was associated with MCI (OR=1.22, 95% CI [1.08, 1.37]) without including any APOE region SNPs. APOE-ϵ4 and APOE-ϵ2 alleles were not associated with MCI.DiscussionA combination of APOE region SNPs is associated with MCI in Hispanics/Latinos despite APOE-ϵ4 and APOE-ϵ2 alleles not being associated with MCI.

Aim: Impaired sleep quality and sleep oxygenation are common sleep pathologies. This study assessed the impact of these abnormalities on white matter (WM) integrity in an epidemiological cohort. Methods: The target population was the Framingham Heart Study Generation-2/Omni-1 Cohorts. Magnetic resonance imaging (diffusion tensor imaging) was used to assess WM integrity. Wearable digital devices were used to assess sleep quality: the (M1-SleepImageTM system) and the Nonin WristOx for nocturnal oxygenation. The M1 device collects trunk actigraphy and the electrocardiogram (ECG); sleep stability indices were computed using cardiopulmonary coupling using the ECG. Two nights of recording were averaged. Results: Stable sleep was positively associated with WM health. Actigraphic periods of wake during the sleep period were associated with increased mean diffusivity. One marker of sleep fragmentation which covaries with respiratory chemoreflex activation was associated with reduced fractional anisotropy and increased mean diffusivity. Both oxygen desaturation index and oxygen saturation time under 90% were associated with pathological directions of diffusion tensor imaging signals. Gender differences were noted across most variables, with female sex showing the larger and significant impact. Conclusions: Sleep quality assessed by a novel digital analysis and sleep hypoxia was associated with WM injury, especially in women.

Background Low socioeconomic status (SES) in early and late life has been associated with lower late-life cognition. Less is known about how changes in SES from childhood to late life are associated with late-life cognition, especially among diverse populations of older adults. Methods In a multi-ethnic sample (n = 1353) of older adults, we used linear regression to test associations of change in comprehensive measures of SES (financial, cultural, and social domains) from childhood to late life with semantic memory, episodic memory, and executive function. We tested whether the association between SES trajectory and late-life cognition differed by populations who resided in the U.S. during childhood or immigrated to the U.S. as adults. Results Participants with low childhood/high late-life financial capital had better semantic memory (β = 0.18; 95% CI: 0.04, 0.32) versus those with low financial capital in both childhood and late life, regardless of childhood residence. We observed a significant interaction in the association of verbal episodic memory and cultural capital by childhood residence (p = 0.08). Participants with a foreign childhood residence had higher verbal episodic memory if they had low childhood/high late-life cultural capital (β = 0.32; 95% CI: 0.01, 0.63), but lower verbal episodic memory if they had high childhood/low late-life cultural capital (β = − 0.40; 95% CI: − 0.94, 0.13). Having high lifecourse social capital was associated with better verbal episodic memory scores among those with a U.S. childhood (β = 0.34; 95% CI: 0.14, 0.55), but lower verbal episodic memory among those with a foreign childhood (β = − 0.10; 95% CI: − 0.51, 0.31). Conclusions High financial and cultural capital in late life is associated with better cognition, regardless of early childhood SES or childhood residence.